This read-only enumerated object reports the link speed of a stacking channel as none(0), speed_10G(1), or speed_12G(2), despite the source description mistakenly repeating the neighbor-slot description rather than describing speed. Admins use this to confirm the stacking interconnect is running at its expected bandwidth, since a lower speed could bottleneck inter-unit traffic. For example, seeing speed_10G reported on a channel expected to run at 12G would suggest a cabling or module mismatch limiting that stacking link's throughput.